Seasickness is caused by the movements of a boat on the water, which disturb the balance sensors in the inner ear, sometimes causing nausea. There are a number of techniques which can be used to prevent seasickness, from acupressure wrist bands to medications which are supposed to reduce nausea. With a few measures taken before sailing, you can greatly reduce the probability of seasickness, and there are also a few things you can do aboard ship which will make you more comfortable.
Before your trip, try eating ginger to prevent seasickness. Mint and chamomile are also supposed to help calm your stomach. You can have ginger tea, ginger candies, or pickled ginger; and you might want to pack a bottle or two of ginger ale for your trip. The carbonation in the ginger ale can help settle your stomach if you start feeling the signs of motion sickness. There are also herbal seasickness remedies which can be found in health food stores, and medications like Dramamine® and Scopamine® are also available in most stores; these medications can be worn on patches or ingested.
Before you sail, get a good night of sleep, because lack of sleep can increase nausea. You should also eat a good breakfast which is free of greasy, heavy, acidic foods. Packing snacks like rolls and muffins is also an excellent idea. Also drink lots of water, as good hydration will help to prevent seasickness.
Once on board, stick to the middle of the boat if you know that you get sea sick, because this part of the boat tends to move the least while the boat is underway. You can also wear an acupressure wrist band, which maintains continuous pressure on a point on your wrist to help prevent nausea. Lots of fresh air can help prevent seasickness as well, and you should steer clear of odorous areas on board ship. If someone else gets seasick while on board, remember that sympathetic reactions do occur.
Experienced sailors say that keeping busy can help prevent seasickness, because you are too distracted to get sick. You might want to ask about taking a turn at the tiller, or performing other tasks on board which could help distract you. If this isn't an option, find someone to chat with, pick up some knitting, or think of another distracting task to focus on. If you do end up getting sick, don't be ashamed; even experienced sailors have off days.